WIP: Begin introducing multi-keystroke bindings to Keymap

src/app/binding-set.coffee

@@ -8,30 +8,39 @@ PEG = require 'pegjs'
 module.exports =
 class BindingSet
   selector: null
-  keystrokeMap: null
+  commandsByKeystrokes: null
   commandForEvent: null
   parser: null
 
   constructor: (@selector, mapOrFunction) ->
     @parser = PEG.buildParser(fs.read(require.resolve 'keystroke-pattern.pegjs'))
     @specificity = Specificity(@selector)
-    @keystrokeMap = {}
+    @commandsByKeystrokes = {}
 
     if _.isFunction(mapOrFunction)
       @commandForEvent = mapOrFunction
     else
-      @keystrokeMap = @normalizeKeystrokeMap(mapOrFunction)
+      @commandsByKeystrokes = @normalizeCommandsByKeystrokes(mapOrFunction)
       @commandForEvent = (event) =>
-        for keystroke, command of @keystrokeMap
-          return command if event.keystroke == keystroke
+        for keystrokes, command of @commandsByKeystrokes
+          return command if event.keystrokes == keystrokes
         null
 
-  normalizeKeystrokeMap: (keystrokeMap) ->
-    normalizeKeystrokeMap = {}
-    for keystroke, command of keystrokeMap
-      normalizeKeystrokeMap[@normalizeKeystroke(keystroke)] = command
+  matchesKeystrokePrefix: (event) ->
+    for keystrokes, command of @commandsByKeystrokes
+      return true if keystrokes.indexOf(event.keystrokes) == 0
+    false
 
-    normalizeKeystrokeMap
+  normalizeCommandsByKeystrokes: (commandsByKeystrokes) ->
+    normalizedCommandsByKeystrokes = {}
+    for keystrokes, command of commandsByKeystrokes
+      normalizedCommandsByKeystrokes[@normalizeKeystrokes(keystrokes)] = command
+    normalizedCommandsByKeystrokes
+
+  normalizeKeystrokes: (keystrokes) ->
+    normalizedKeystrokes = keystrokes.split(/\s+/).map (keystroke) =>
+      @normalizeKeystroke(keystroke)
+    normalizedKeystrokes.join(' ')
 
   normalizeKeystroke: (keystroke) ->
     keys = @parser.parse(keystroke)

src/app/keymap.coffee

@@ -8,6 +8,7 @@ Specificity = require 'specificity'
 module.exports =
 class Keymap
   bindingSets: null
+  queuedKeystrokes: null
 
   constructor: ->
     @bindingSets = []
@@ -40,7 +41,8 @@ class Keymap
     keystrokeMap
 
   handleKeyEvent: (event) ->
-    event.keystroke = @keystrokeStringForEvent(event)
+    event.keystrokes = @multiKeystrokeStringForEvent(event)
+    @queuedKeystrokes = null
     currentNode = $(event.target)
     while currentNode.length
       candidateBindingSets = @bindingSets.filter (set) -> currentNode.is(set.selector)
@@ -52,6 +54,10 @@ class Keymap
           return false
         else if command == false
           return false
+
+        if bindingSet.matchesKeystrokePrefix(event)
+          @queuedKeystrokes = event.keystrokes
+          return false
       currentNode = currentNode.parent()
     true
 
@@ -60,6 +66,13 @@ class Keymap
     commandEvent.keyEvent = keyEvent
     $(keyEvent.target).trigger(commandEvent)
 
+  multiKeystrokeStringForEvent: (event) ->
+    currentKeystroke = @keystrokeStringForEvent(event)
+    if @queuedKeystrokes
+      @queuedKeystrokes + ' ' + currentKeystroke
+    else
+      currentKeystroke
+
   keystrokeStringForEvent: (event) ->
     if /^U\+/i.test event.originalEvent.keyIdentifier
       hexCharCode = event.originalEvent.keyIdentifier.replace(/^U\+/i, '')